|Número de publicación||US4033355 A|
|Tipo de publicación||Concesión|
|Número de solicitud||US 05/635,909|
|Fecha de publicación||5 Jul 1977|
|Fecha de presentación||28 Nov 1975|
|Fecha de prioridad||28 Nov 1975|
|Número de publicación||05635909, 635909, US 4033355 A, US 4033355A, US-A-4033355, US4033355 A, US4033355A|
|Inventores||David Charles Amundson|
|Cesionario original||Cardiac Pacemakers, Inc.|
|Exportar cita||BiBTeX, EndNote, RefMan|
|Citas de patentes (6), Citada por (78), Clasificaciones (9)|
|Enlaces externos: USPTO, Cesión de USPTO, Espacenet|
The present invention relates generally to a lead assembly for the electrodes of an implantable electrical pulse generator delivering stimulating pulses to an internal organ, and more specifically to such a lead assembly which retains a conductor means therewithin, and is provided with a conductive encapsulating tube which will provide electrical continuity and continued conductivity for the assembly in the event of rupture or severance of the conductors. More specifically, the conductive encapsulating tubular element provides both electrical back-up and a compressive force to grip the conductor means therewithin and reduce the extent of migration of the free ends of fractured wires.
In the design of implantable lead assemblies for delivering stimulating electrical pulses from a pulse generator to an internal organ, such as, for example, a cardiac pacer device or the like, the lead assembly must be sufficiently flexible so as to accommodate flexure at a rate, for example, the normal 72 beats per minute of the human heart. In the past, various types and combinations of conductor means have been employed, and in particular a coiled lead wound in the form of a helix has been widely used. These leads are normally metallic conductors, and have been fabricated from stainless steel such as MT 35 stainless. This material is sufficiently flexible so as to permit its use in implanted lead assemblies.
As has been indicated, and recognized in the art, implantable leads must be sufficiently flexible so as to not interfere with the normal function of delicate systems within the patient. At the same time, these leads must be sufficiently durable so as to withstand substantially constant flexural motion, while, at the same time, withstanding such flexural motion at localized zones or areas along the extent of the lead. Upon occasion, the conductor system may become separated due to fracture, and when this occurs in the assembly of the present invention, conductivity continues by virtue of a conductive sleeve which is arranged to compressively grip the coiled conductors. The structure of the present invention provides an electrically conductive path which is designed so to not be adversely affected by those same forces which tend to either damage or destroy the continuity of the metallic conductor.
Briefly, in accordance with the present invention, the lead assembly utilizes a core in the form of a coiled conductor or conductors which are wound in the form of a helix, and wherein a semi-conducting silicone rubber is arranged so as to compressively grip the outer diameter of the conductive helix. The semi-conductive tubular element is, in turn, encapsulated within an outer insulative tubular element, with the outer tube, in turn, compressively gripping the outer diameter of the inner tubular element. This arrangement provides for a highly flexible lead assembly which is durable and yet provides for continued functional operation even upon the occurrence of a break, such as a fracture or other undesireable separation of the coiled lead.
Therefore, it is the primary object of the present invention to provide an improved implantable lead assembly and method of preparation thereof wherein the assembly is arranged for coupling a stimulating pulse generator to an internal organ, with the lead assembly including means at one end for coupling to the output of a pulse generator, and with conductive electrodes or tips being disposed at the distal or free end of the lead.
It is a further object of the present invention to provide an improved implantable electrode lead assembly for coupling the output of an electrical pulse generator to an internal organ wherein the lead assembly includes a coiled electrical conductor wound about a central axis to form a helix, and wherein the coiled conductor is compressively gripped within a semi-conductive silicone rubber tube, with the semi-conductive tube being, in turn, compressively gripped within a second or outer insulative tubular element.
It is yet a further object of the present invention to provide an improved implantable electrode lead assembly and method of preparing same wherein the lead assembly is arranged for coupling the output of an electrical pulse generator to a conductive electrode tip wherein conductors are provided in the form of a coiled helix, with the helix being encapsulated within inner and outer tubular elements, the inner tubular element being in the form of a semi-conductive silicone rubber which is treated to expand for reception of the conductor, and thereafter to shrink and return to its original configuration, the inner tubular element compressively gripping the outer diameter of the coiled conductor helix, and with the semi-conductive tubular element being, in turn, being similarly encapsulated and compressively gripped within an insulative outer tubular element.
These and other objects of the present invention will become apparent to those skilled in the art upon a study of the following specification, appended claims, and the accompanying drawing.
FIG. 1 is a block diagram of a method employed to prepare the improved implantable electrode lead assemblies of the present invention;
FIG. 2 is a plan elevational view of a typical pulse generator having the implantable electrode lead assembly of the present invention operatively secured thereto, with a portion of the lead assembly being broken away;
FIG. 3 is a detail sectional view of a segment of the lead assembly, with FIG. 3 being shown on a slightly enlarged scale, and illustrating the detail of the lead;
FIG. 4 is a detail perspective view of the electrode lead assembly of the present invention, and illustrating the coiled conductor along with the tubular elements encapsulating the conductor, with the conductor and the tubular elements being partially broken away, and with FIG. 4 also being shown on a slightly enlarged scale.
In accordance with the preferred embodiment of the present invention, and with particular attention being directed to FIG. 2 of the drawing, the cardiac pacer assembly generally designated 10 includes a pulse generator enclosed within casing 11, having a lead attachment head shown at 12. The pulse generator is shown at 13, it being understood, of course, that pulse generator 13 is enclosed generally within casing 11. Lead assembly 14 is shown coupled to the pulse generator, with lead assembly 14 extending from coupling zone or station 12 to the conductive electrode tip shown at 15. Conductive tip 15 is, of course, exposed and is generally in physical contact with the tissue to be stimulated, such as the heart muscle in the case of the cardiac pacer device.
The arrangement of the device illustrated in FIG. 2 is that of an unipolar cardiac pacer, and the assembly may be in the form of that assembly disclosed and claimed in U.S. Pat. No. 3,822,707. The circuitry for the pulse generator 13 may be in the form of that circuitry disclosed in co-pending application Ser. No. 515,463, filed Oct. 17, 1974 and now abandoned, and entitled "CARDIAC PACER CIRCUIT", Jon A. Anderson and Richard W. Kramp, which application is assigned to the same assignee as the present application.
In order to couple the lead to the pulse generator, a coupling arrangement is illustrated generally at 16, with the arrangement including a sleeve or the like 17 in head 12 for receiving the proximal end of the lead, and with the conductor per se being clampingly engaged by set screw 18 prior to final implantation. Preferably, the entire head 12 which is spaced from casing 11 is fabricated from a clear and transparent material so as to permit a visual sighting of the conductor portion 19 as it extends through the area from the set screw.
It will be appreciated, of course, that bipolar leads may be prepared utilizing the features of the present invention which provide for continued conductivity between portions of the individual conductor elements either of which may become separated due to fracture of the conductor. For purposes of comprehending the concept, however, a unipolar device is disclosed for simplicity.
Attention is now directed to FIGS. 3 and 4 of the drawing wherein the details of the lead assembly are illustrated. Specifically, as illustrated in FIG. 3, the conductor system generally designated 20 includes a pair of parallel spans 21 and 22, each of which is arranged in a helical pattern about a common axis. Also, the coiled conductors have a generally uniform outer diameter, as is apparent in FIGS. 3 and 4. A pair of coaxially disposed tubular elements 24 and 25 enclose the coiled conductors 21 and 22 as will be more fully explained hereinafter.
In the embodiment illustrated, the first tubular element 24 is disposed about the outer periphery of the conductor, with tubular element 24 compressively gripping the outer diameter. Preferably, tubular element 24 is prepared from semi-conducting silicone rubber, and preferably has an electrical resistivity of less than about 130 ohm-cm. and even more preferably less than about 100 ohm-cm. The outer tubular element 25 is, as indicated, electrically insulating, and also compressively grips the outer periphery of the inner tubular element 24. It is desireable that the outer tubular element compressively grip the inner tubular element so as to improve the flexural characteristics of the assembly, without introducing frictional contact between the mutually mating surfaces of the inner and outer tubular elements.
As has been indicated, the material of construction for the conductors is preferably stainless steel type MT 35. This material is substantially inert to body fluids, and also possesses mechanical properties which include the requisite flexural characteristics and tensile strength. Resistance to fatigue is a further consideration. In the embodiment illustrated, a pair of coiled conductors are provided, it being appreciated, or course, that a single coiled conductor may be useful in certain installations, and in certain other installations or applications more than two such coils could be found useful.
Typically, for cardiac pacer applications, the conductor normally has a diameter of 0.006 inches, and is coiled as to form a helix having a diameter of approximately 0.035 inches. For most purposes, the helix will have a pitch of about 0.014 inches.
While stainless steel has been recommended, for certain other applications, platinum or platinum-iridium alloys may be required, although for most applications stainless steel has been found reasonably useful and applicable.
For the preparation of the tubular element 24, an electrically semi-conductive silicone rubber is utilized. Such materials are, of course, commercially available, with one such material found useful being that certain silicone rubber sold under the code designation Silastic S-2086 by Dow Corning Corporation of Midland, Michigan. This material, as molded, has an electrical resistivity of approximately 60 ohm-cm., but when cured for 24 hours at a temperature of approximately 250 degrees C. the resistivity drops to approximately 8 ohm-cm.
The outer tubular element 25, as previously indicated, is essentially insulative in nature. Any silicone rubber may be employed, with one such rubber being medical grade Silastic Tubing and available from Dow Corning Corporation of Midland, Michigan, and approved for use as an implantable device or component.
As previously indicated, the electrode tips such as is illustrated at 15 are typically prepared from stainless steel of type MT 35. These tips are, of course, exposed directly to the tissue being stimulated and, as such, comprise the active element delivering the stimulator pulse to the patient from the pulse generator.
In order to prepare the assembly, the coiled conductor is placed within the interior of a semi-conductive tubular element such as the element 24, with the tubular element having an internal diameter less than the outer diameter of the conductor helix. For a conductor helix having an outer diameter of, for example, 0.035 inches, the tubular element should have an internal diameter of approximately 0.034 inches. The tubular element is immersed in a material which causes expansion of the tubing, such as, for example, a fluorinated hydrocarbon such as Freon, preferably a Freon which remains in liquid state under ordinary ambient conditions. As an alternate, xylene or toluene may be employed for expanding the tubing. In this connection, therefore, the tubing is immersed in the Freon or other selected material until expansion occurs, and sufficient expansion for receiving the coiled helix therewithin. Following introduction of the conductor in the form of a coiled helix therewithin, the combination is baked until the solvent is driven off, with a baking for a period of six hours at 250 degrees C. normally being sufficient.
The semi-conductive tubing, as indicated, has a post-cure inner diameter of about 0.034 inches, with a wall thickness sufficient to provide an outer diameter of about 0.060 inches. The outer tubing is selected so as to provide an interference fit with the outer periphery of the inner tubing. In this connection, with an inner tubing having an outer diameter of about 0.060 inches, the outer tubing will have an inner diameter of approximately 0.060 inches as well, with the outer tubing being likewise immersed in Freon, xylene, or toluene so as to expand the tubing to receive the inner tubing therewithin. Following such treatment, the structure is again baked or post-cured at a temperature of approximately 250 degrees C. for a period of about 6 hours. Such a post-cure or baking cycle is sufficient to remove any residual solvent which may remain, and provide a system which is acceptable as an implantable device.
As has been indicated, the resistivity of the inner tubing is selected so as to be between about 8 ohm-cm. and 130 ohm-cm. Typically, in a stimulator such as a cardiac pacer device, the electrical load is normally in the area of approximately 500 ohms. For stimulation of a muscle such as the heart, 1 to 2 milliamperes are required. With a pulse generator having an output of 5 volts for stimulating the heart muscle, it will be appreciated that an impedence of up to 5,000 ohms could reasonably be handled. Typically, the system will be designed so as to provide power of the order of 10 milliamps for the muscle stimulation, however, as indicated, 1 to 2 milliamperes will normally be sufficient to stimulate the heart muscle.
In the coiled assembly, the tubular element 24 compressively grips the conductors 21 and 22 therewithin. In view of the compressive gripping forces, it has been ascertained that, for most purposes, any fracture or break in the conductor would not normally place or position the fractured ends at a distance greater than about 1 millimeter, one from the other. Therefore, in order to increase the resistance to an overall magnitude of less than 5,000 ohms, a resistivity of less than about 130 ohm-cm. will be required. The spreading resistance of the system when confronted with a conductor separation of about 1 millimeter will accommodate the arrangement when the resistivity is below about 130 ohm-cm. in this embodiment. Generally, a resistivity range of between about 10 ohm-cm. and 100 ohm-cm. is highly workable. Therefore, a system is provided which retains the mechanical properties of flexibility and durability, without sacrificing of the electrical properties. As indicated above, the forces which normally damage or destroy the metallic conductors do not adversely affect the conductive path provided by the semi-conductive rubber member.
The present invention provides an implantable electrode lead assembly which is self-healing in the event of a break occuring in the conductor element per se. The system is one which permits a patient time, upon occurence of the fracture, to seek medical aid in the form of a replacement of the damaged lead. When applied to a cardiac pacer, the patient will, in most instances, have sufficient time to seek and obtain medical aid and replacement of the lead.
|Patente citada||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US2377153 *||6 Jun 1942||29 May 1945||Callenders Cable & Const Co||Electric cable|
|US3284562 *||8 Feb 1965||8 Nov 1966||Dow Corning||Flexible electrical conductor|
|US3474791 *||24 Mar 1966||28 Oct 1969||Brunswick Corp||Multiple conductor electrode|
|US3924639 *||17 Jul 1974||9 Dic 1975||Cordis Corp||Cardiac pacer lead system for interim pacing during pacer changeover|
|DE84040C *||Título no disponible|
|SU311643A1 *||Título no disponible|
|Patente citante||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US4161952 *||1 Nov 1977||24 Jul 1979||Mieczyslaw Mirowski||Wound wire catheter cardioverting electrode|
|US4220386 *||9 Mar 1978||2 Sep 1980||Needle Industries Limited||Plug and socket connectors|
|US4230127 *||24 May 1978||28 Oct 1980||Medtronic, Inc.||Cardiac monitoring apparatus|
|US4262982 *||11 Abr 1979||21 Abr 1981||Needle Industries Ltd.||Electrical socket useful for connecting an electrode catheter to a cardiac pacemaker casing|
|US4273137 *||17 Dic 1979||16 Jun 1981||Pravoverov Nikolai L||Electrical conductor for implantation into human body|
|US4280507 *||27 Jun 1979||28 Jul 1981||Hewlett-Packard Company||Patient cable with distributed resistance protection in conductors|
|US4469104 *||16 Jul 1982||4 Sep 1984||Cordis Corporation||Multipolar connector for pacing lead|
|US4559951 *||29 Nov 1982||24 Dic 1985||Cardiac Pacemakers, Inc.||Catheter assembly|
|US4573480 *||19 Dic 1983||4 Mar 1986||Siemens Aktiengesellschaft||Implantable electrode lead with microporous insulation|
|US5358516 *||11 Dic 1992||25 Oct 1994||W. L. Gore & Associates, Inc.||Implantable electrophysiology lead and method of making|
|US5466252 *||2 Oct 1992||14 Nov 1995||W. L. Gore & Associates, Inc.||Implantable lead|
|US5569883 *||31 Ago 1994||29 Oct 1996||Pacesetter, Inc.||Joint for providing a secure connection between a wound element and a mating part in a body implantable lead assembly and method for making such joint|
|US5609622 *||12 Dic 1995||11 Mar 1997||W. L. Gore & Associates, Inc.||Implantable electrode with conductive polytetrafluoroethylene elecrode|
|US5843149 *||7 Nov 1996||1 Dic 1998||Medtronic, Inc.||Electrical lead insulator|
|US6018683 *||30 Abr 1998||25 Ene 2000||Medtronic, Inc.||Medical electrical lead having coiled and stranded conductors|
|US6061598 *||10 Feb 1999||9 May 2000||Medtronic, Inc.||Fracture resistant medical electrical lead|
|US6119042 *||13 Ene 2000||12 Sep 2000||Medtronic, Inc.||Medical electrical lead|
|US6285910||21 Abr 1997||4 Sep 2001||Medtronic, Inc.||Medical electrical lead|
|US6785576||25 Mar 2002||31 Ago 2004||Medtronic, Inc.||Medical electrical lead|
|US6900055||28 Oct 1999||31 May 2005||Cellon S.A.||Preparation of porous silicone rubber for growing cells or living tissue|
|US6915169||4 Oct 2002||5 Jul 2005||Cardiac Pacemakers, Inc.||Extendable and retractable lead having a snap-fit terminal connector|
|US6983185||31 Jul 2002||3 Ene 2006||Cardiac Pacemakers, Inc.||Lead with terminal connector assembly|
|US7065411||23 Abr 2003||20 Jun 2006||Medtronic, Inc.||Electrical medical leads employing conductive aerogel|
|US7392095||1 Jul 2005||24 Jun 2008||Cardiac Pacemakers, Inc.||Extendable and retractable lead having a snap-fit terminal connector|
|US7519432||29 Abr 2005||14 Abr 2009||Medtronic, Inc.||Implantable medical lead with helical reinforcement|
|US7660635||14 Jul 2000||9 Feb 2010||Medtronic, Inc.||Medical electrical lead|
|US7761170||29 Abr 2005||20 Jul 2010||Medtronic, Inc.||Implantable medical lead with axially oriented coiled wire conductors|
|US7774934||8 Dic 2005||17 Ago 2010||Cardiac Pacemakers, Inc.||Method for making a terminal connector|
|US7831311||29 Abr 2005||9 Nov 2010||Medtronic, Inc.||Reduced axial stiffness implantable medical lead|
|US7930038 *||27 May 2005||19 Abr 2011||Cardiac Pacemakers, Inc.||Tubular lead electrodes and methods|
|US7949412||1 Jun 2006||24 May 2011||Advanced Bionics, Llc||Coated electrode array having uncoated electrode contacts|
|US8190271||29 May 2012||Advanced Bionics, Llc||Minimizing trauma during and after insertion of a cochlear lead|
|US8209035||26 Jun 2012||Cardiac Pacemakers, Inc.||Extendable and retractable lead having a snap-fit terminal connector|
|US8271101||31 Jul 2009||18 Sep 2012||Advanced Bionics||Modular drug delivery system for minimizing trauma during and after insertion of a cochlear lead|
|US8280526 *||2 Oct 2012||Medtronic, Inc.||Extensible implantable medical lead|
|US8285398||7 Jul 2010||9 Oct 2012||Cardiac Pacemakers, Inc.||Lead with terminal connector assembly|
|US8380325||19 Feb 2013||Boston Scientific Neuromodulation Corporation||Systems and methods for coupling coiled conductors to conductive contacts of an electrical stimulation system|
|US8577476||9 Mar 2011||5 Nov 2013||Biotectix, LLC||Electrically conductive and mechanically supportive materials for biomedical leads|
|US9026213 *||13 Jul 2012||5 May 2015||Cardiac Pacemakers, Inc.||Medical device lead with conductor fracture prediction|
|US9050454||4 Nov 2013||9 Jun 2015||Biotectix, LLC||Electrically conductive and mechanically supportive polymer materials for biomedical leads|
|US9186499||27 Abr 2010||17 Nov 2015||Medtronic, Inc.||Grounding of a shield within an implantable medical lead|
|US9190793||15 Feb 2013||17 Nov 2015||Boston Scientific Neuromodulation Corporation||Systems and methods for coupling coiled conductors to conductive contacts of an electrical stimulation system|
|US9205253||27 Abr 2010||8 Dic 2015||Medtronic, Inc.||Shielding an implantable medical lead|
|US9216286||28 Abr 2010||22 Dic 2015||Medtronic, Inc.||Shielded implantable medical lead with guarded termination|
|US9220893||1 Dic 2014||29 Dic 2015||Medtronic, Inc.||Shielded implantable medical lead with reduced torsional stiffness|
|US9259572||2 Jun 2014||16 Feb 2016||Medtronic, Inc.||Lead or lead extension having a conductive body and conductive body contact|
|US9272136||11 Ago 2014||1 Mar 2016||Medtronic, Inc.||Grounding of a shield within an implantable medical lead|
|US9295833||31 May 2005||29 Mar 2016||St. Jude Medical, AB||Implantable medical lead|
|US9302101||17 Mar 2014||5 Abr 2016||Medtronic, Inc.||MRI-safe implantable lead|
|US20040215300 *||23 Abr 2003||28 Oct 2004||Medtronic, Inc.||Electrical medical leads employing conductive aerogel|
|US20050246007 *||28 Abr 2004||3 Nov 2005||Medtronic, Inc.||Novel lead body assemblies|
|US20060089691 *||29 Abr 2005||27 Abr 2006||Medtronic, Inc.||Implantable medical lead with axially oriented coiled wire conductors|
|US20060089692 *||29 Abr 2005||27 Abr 2006||Medtronic, Inc.||Implantable medical lead with stylet guide tube|
|US20060089695 *||29 Abr 2005||27 Abr 2006||Medtronic, Inc.||Implantable medical lead with helical reinforcement|
|US20060089697 *||29 Abr 2005||27 Abr 2006||Medtronic, Inc.||Implantable medical lead|
|US20060200218 *||1 Feb 2006||7 Sep 2006||Wahlstrand Carl D||Extensible implantable medical lead|
|US20060265037 *||6 Nov 2002||23 Nov 2006||Kuzma Janusz A||Construction of cylindrical multicontact electrode lead for neural stimulation and method of making same|
|US20070038278 *||27 May 2005||15 Feb 2007||Cardiac Pacemakers, Inc.||Tubular lead electrodes and methods|
|US20070179582 *||31 Ene 2006||2 Ago 2007||Marshall Mark T||Polymer reinforced coil conductor for torque transmission|
|US20080146894 *||19 Dic 2007||19 Jun 2008||Cherik Bulkes||Signal sensing in an implanted apparatus with an internal reference|
|US20090062896 *||29 Ago 2008||5 Mar 2009||Overstreet Edward H||Minimizing Trauma During and After Insertion of a Cochlear Lead|
|US20090125090 *||31 May 2005||14 May 2009||Kenth Nilsson||Implantable medical lead|
|US20090292237 *||26 Nov 2009||Advanced Bionics, Llc||Modular Drug Delivery System for Minimizing Trauma During and After Insertion of a Cochlear Lead|
|US20100114271 *||31 Oct 2008||6 May 2010||Medtronic, Inc.||Shielded conductor filar - stimulation leads|
|US20110034978 *||5 Ago 2009||10 Feb 2011||Boston Scientific Neuromodulation Corporation||Systems and methods for coupling coiled conductors to conductive contacts of an electrical stimulation system|
|US20110301680 *||8 Dic 2011||Medtronic, Inc.||Medical electrical lead|
|US20120330383 *||30 Ago 2012||27 Dic 2012||Wahlstrand Carl D||Extensible Implantable Medical Lead|
|US20130041444 *||13 Jul 2012||14 Feb 2013||Arthur J. Foster||Medical device lead with conductor fracture prediction|
|DE3043189A1 *||15 Nov 1980||3 Jun 1982||Osypka Peter||Compact heart pacemaker electrode - has coaxial windings for separate electrode pole conductors|
|EP0739642A2 *||9 Abr 1996||30 Oct 1996||INCONTROL, Inc.||Cardiac lead with composite insulating structure|
|EP1023915A1||18 Mar 1998||2 Ago 2000||Medtronic, Inc.||Medical electrical lead|
|EP2079511A1 *||22 Oct 2007||22 Jul 2009||BULKES, Cherik||Mri compatible implanted electronic medical device and lead|
|WO1994013358A1 *||28 Jul 1993||23 Jun 1994||W.L. Gore & Associates, Inc.||An implantable electrophysiology lead|
|WO1998047560A1||18 Mar 1998||29 Oct 1998||Medtronic, Inc.||Medical electrical lead|
|WO2000024437A2 *||28 Oct 1999||4 May 2000||Ashby Scientific Ltd.||Textured and porous silicone rubber|
|WO2000024437A3 *||28 Oct 1999||19 Oct 2000||Ashby Scient Ltd||Textured and porous silicone rubber|
|WO2006130056A1 *||31 May 2005||7 Dic 2006||St. Jude Medical Ab||Implantable lead|
|WO2013052066A1 *||7 Oct 2011||11 Abr 2013||Advanced Bionics Ag||Lead body with tubes of different diameters for a cochlear implant|
|Clasificación de EE.UU.||607/122, 174/120.0SC|
|Clasificación internacional||H01B7/00, H01B7/04, A61N1/05|
|Clasificación cooperativa||H01B7/0009, H01B7/0054, A61N1/056|